Good morning Weather2020 bloggers,

The incredible cycling pattern is set for the season.  We are moving into the second cycle of this year’s  features of this year’s pattern.  When will they return? What will they mean as we move through this winter season when they do return? Will California get blasted by massive winter storm systems as is being advertised by what is supposed to happen during a strong El Niño winter?  We will be answering these questions in the next few days and weeks.

LRC INDEX December 7

Here is the first cycle of this year’s pattern, and likely the first ten days of the second cycle. The pattern that is developing this week will feature a pretty big warm-up across a large part of the nation, and then within the next week a big change will happen.

The pattern forming now is quite similar to close to 50 days ago.  There is a signature “look” to the pattern that we have been waiting on, and it appears to be showing up in next weeks storm system.  How will it actually set up, and what areas will be targeted by the warm side of this storm, and which areas will be targeted by the cold side of this storm is yet to be determined.  We do know that the AO and NAO indexes have continued to be positive and this favors a more unblocked and farther north track.  This is not set in stone yet, so let’s see how it evolves in the coming days.

You can see this storm on the computer models now. On this model from the midnight run of last night’s GFS model an upper low is forecast to develop over Utah by one week from tonight. The models have varying strengths of this system, but most of them now track  it north of Kansas City. For it to snow in KC we will need the main disturbance to track farther south than the trend has been showing, and this is a possibility. We do have, however, a split of the southwestern Canada coast forecast to develop, and the northern stream continues to be rather flat:


Now, before we even get to this storm, take a look at the warm pattern we are in this week:


We have what is called a mostly zonal jet stream, from west to east, but by the end of the week a big dip in the flow is forecast to develop:


Before we get to any significant changes in the winter direction we have a big warming trend first. Take a look at this level, the 850 mb forecast (5,000 feet up) showing the lack of any cold air:


This is a warm pattern out ahead of next week’s change and temperatures will likely get close to record highs in many areas. The AO is forecast to dip into negative territory next week, and I have seen some model runs start to block up the pattern. It is something we have to monitor closely as it could have an impact on next week’s storm.

Have a great day, and thank you for participating in the LRC Forecast Experience Blog.  Have you entered our contest yet. You have one more week to enter as we are forecasting for the Christmas week. Click here to enter:  Long Range Weather Forecast Contest